[llvm-commits] CVS: llvm/lib/Target/X86/X86ISelSimple.cpp

[Chris Lattner]

Changes in directory llvm/lib/Target/X86:

X86ISelSimple.cpp updated: 1.301 -> 1.302
---
Log message:

Create a stack slot for the return address lazily instead of eagerly.  This
save small amounts of time for functions that don't call llvm.returnaddress
or llvm.frameaddress (which is almost all functions).


---
Diffs of the changes:  (+8 -4)

Index: llvm/lib/Target/X86/X86ISelSimple.cpp
diff -u llvm/lib/Target/X86/X86ISelSimple.cpp:1.301 llvm/lib/Target/X86/X86ISelSimple.cpp:1.302
--- llvm/lib/Target/X86/X86ISelSimple.cpp:1.301	Mon Dec 13 11:23:11 2004
+++ llvm/lib/Target/X86/X86ISelSimple.cpp	Thu Dec 16 18:07:46 2004
@@ -96,6 +96,9 @@
     /// the entire function.
     ///
     bool runOnFunction(Function &Fn) {
+      // Lazily create a stack slot for the return address if needed.
+      ReturnAddressIndex = -1;
+
       // First pass over the function, lower any unknown intrinsic functions
       // with the IntrinsicLowering class.
       LowerUnknownIntrinsicFunctionCalls(Fn);
@@ -108,10 +111,6 @@
 
       BB = &F->front();
 
-      // Set up a frame object for the return address.  This is used by the
-      // llvm.returnaddress & llvm.frameaddress intrinisics.
-      ReturnAddressIndex = F->getFrameInfo()->CreateFixedObject(4, -4);
-
       // Copy incoming arguments off of the stack...
       LoadArgumentsToVirtualRegs(Fn);
 
@@ -1765,6 +1764,11 @@
   case Intrinsic::frameaddress:
     TmpReg1 = getReg(CI);
     if (cast<Constant>(CI.getOperand(1))->isNullValue()) {
+      if (ReturnAddressIndex == -1) {
+        // Set up a frame object for the return address.
+        ReturnAddressIndex = F->getFrameInfo()->CreateFixedObject(4, -4);
+      }
+
       if (ID == Intrinsic::returnaddress) {
         // Just load the return address
         addFrameReference(BuildMI(BB, X86::MOV32rm, 4, TmpReg1),